In recent years, with the trend toward a reduction in the size and weight of electronic devices, there has also been a demand for electronic components constituting electronic devices, such as coils, in which a reduction in the size and an increase in the density of conductive patterns are achieved. In order to meet the demand, as a replacement for conventional coils in which electric wires are wound around magnetic materials, a flexible printed circuit board having a coil pattern on a substrate has been developed (refer to Patent Literature 1).
However, in the flexible printed circuit board, a photolithographic technique using a resist pattern is employed to form a conductive pattern constituting the coil. For this reason, the linewidth and pitch of the conductive pattern depend on the linewidth and pitch of the resist pattern, which limits increase in the density of the conductive pattern.